It’s a space rock about 2 kilometers in diameter that looks as if it might have fallen straight out of The Little Prince. There are three key things to know about 3554 Amun: First, its orbit crosses that of Earth; second, it’s the smallest M-class (metal-bearing) asteroid yet discovered; and finally, it contains (at today’s prices) roughly $8 trillion worth of iron and nickel, $6 trillion of cobalt, and $6 trillion of platinumlike metals. In other words, whoever owns Amun could become 450 times as wealthy as Bill Gates. And if you time your journey right — 2020 looks promising — it’s easier to reach than the Moon.